| Autor: |
Macías-Macías JO; Centro de Investigaciones en Abejas (CIABE), Centro Universitario del Sur, Universidad de Guadalajara, Enrique Arreola Silva 883, Cd., Guzman, Jal., Mexico., Tapia-Rivera JC; Centro de Investigaciones en Abejas (CIABE), Centro Universitario del Sur, Universidad de Guadalajara, Enrique Arreola Silva 883, Cd., Guzman, Jal., Mexico., De la Mora A; School of Environmental Sciences, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada., Tapia-González JM; Centro de Investigaciones en Abejas (CIABE), Centro Universitario del Sur, Universidad de Guadalajara, Enrique Arreola Silva 883, Cd., Guzman, Jal., Mexico., Contreras-Escareño F; Depto. de Producción Agrícola, Centro de Investigaciones en Abejas (CIABE), Centro Universitario de la Costa Sur, Universidad de Guadalajara, Independencia Nal. 161, Autlan, Jal., Mexico., Petukhova T; Dept. Population Medicine, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada., Morfin N; School of Environmental Sciences, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada., Guzman-Novoa E; Centro de Investigaciones en Abejas (CIABE), Centro Universitario del Sur, Universidad de Guadalajara, Enrique Arreola Silva 883, Cd., Guzman, Jal., Mexico. eguzman@uoguelph.ca.; School of Environmental Sciences, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada. eguzman@uoguelph.ca. |
| Abstrakt: |
The microsporidian parasite Nosema ceranae and neonicotinoid insecticides affect the health of honey bees (Apis mellifera). However, there is limited information about the effect of these stressors on other pollinators such as stingless bees (Hymenoptera: Meliponini). We examined the separate and combined effects of N. ceranae and the neonicotinoid thiamethoxam at field-exposure levels on the survivorship and cellular immunity (hemocyte concentration) of the stingless bee Melipona colimana. Newly-emerged bees were subjected to four treatments provided in sucrose syrup: N. ceranae spores, thiamethoxam, thiamethoxam and N. ceranae, and control (bees receiving only syrup). N. ceranae developed infections of > 467,000 spores/bee in the group treated with spores only. However, in the bees subjected to both stressors, infections were < 143,000 spores/bee, likely due to an inhibitory effect of thiamethoxam on the microsporidium. N. ceranae infections did not affect bee survivorship, but thiamethoxam plus N. ceranae significantly increased mortality. Hemocyte counts were significantly lower in N. ceranae infected-bees than in the other treatments. These results suggest that N. ceranae may infect, proliferate and cause cellular immunosuppression in stingless bees, that exposure to sublethal thiamethoxam concentrations is toxic to M. colimana when infected with N. ceranae, and that thiamethoxam restrains N. ceranae proliferation. These findings have implications on pollinators' conservation. |
